2-Haloalkyl-haloalkylsulfonylbenzimidazoles

ABSTRACT

Compounds of formula   IN WHICH R1 is hydrogen, -CF2H, -CFClH or -CCl2H and R2 is (C12) halogenalkyl, are valuable herbicides.

United States Patent Horlein et al.

Hoechst Aktiengesellschaft, Frankfurt am Main, Germany Filed: May 23, 1974 Appl. No.: 472,800

Assignee:

Foreign Application Priority Data May 25, 1973 Germany 2326624 US. Cl. 260/309.2; 71/92; 260/578 Int. Cl C07d 49/38 Field of Search 260/309.2

[56] References Cited UNITED STATES PATENTS 11/1968 Zwahlen 260/309.2 6/1972 Frick 260/309.2

OTHER PUBLICATIONS Bannert, et al., Chem. Abst., 1973, Vol. 78, N0. 99066w, QDLASI.

[451 June 17, 1975 Sedova, et al., Chem. Abst.,

1970, Vol. 72, No. 31366q, QD1.A51.

Troitskaya, et al., Chem. Abst., 1973, Vol. 79, No.

54858k, QDLASI.

Yagupolskii, et al., Chem. Abst., 1959, Vol. 53, col umns 21765-217656, QD1.A'51.

Primary Examiner-Natalie Trousof Attorney, Agent, or Firm-Curtis, Morris and Safford 57 ABSTRACT Compounds of formula in which R is hydrogen, -CF H, -CFCll-l or CCl l-l and R is (C halogenalkyl, are valuable herbicides.

2 Claims, N0 Drawings Z-HALOALKYL-HALOALKYLSULFONYLBEN- ZIMIDAZOLES The herbicidal action of numerous benzimidazoles substituted in 2-position by haloalkyl is known (Dutch Pat. application No. 6 700 130; Belgian Pats. Nos. 659 384 and 697 288; Z. Naturforsch. Part B, 25 (1970), 934-944).

The present invention relates to benzimidazole derivatives of the formula where R is H, -CF H, -CFClH or -CCl H and R is haloalkyl having 1 or 2 carbon atoms.

The present invention relates furthermore to a process for the preparation of compounds of formula I, which comprises reacting o-phenylenediamine derivatives of the formula IR CF SO with aliphatic halocarboxylic acids of the formula R COOH lll or the functional derivatives thereof.

The reaction of the compounds of formula ll to form the compounds of the invention is carried out in known manner by reacting an o-phenylene-diamine derivative 1] with a halocarboxylic acid III or a functional derivative thereof. Such functional derivatives are for example esters of halocarboxylic acids with lower alcohols, furthermore anhydrides, acid halides, especially acid chlorides, imino ethers or amidines. In these com pounds, R may for example stand for the following radicals: -CF --CCl CBr CHCL --CH Cl, --CF CF CCl CCl -CCl CH -CHClCH CF CCl H.

The use of an inert solvent, preferably glacial acetic acid, is generally advantageous; however, when the free acids are employed, an excess of from 50 to 100 of free acid over the theory is sufficient. Depending on the reactivity of the reactants, the reaction temperatures are in the range of from 40 to 120C; the operations being preferably carried out at the reflux temperature of the reaction mixture. After completion of the reaction the solvent or the excess of component III is distilled off advantageously together with the water formed. The reaction products remain as solid residues which, optionally, may be purified by recrystallization.

The compounds of formula I have an excellent selective herbicidal activity, especially in hard-to-combat dicotyledonous weeds, and they may therefore be applied as herbicides in combination with usual formulating additives such as adhesives, wetting and dispersing agents, liquid or solid carrier materials, grinding auxiliaries, or granulating agents. Other herbicidal agents and/or fertilizers may also be added.

The starting substances of formula ll may be obtained according to known methods, starting from 2- or 4-chloro-mercaptophenol (see also Example la and 2f) according to the following scheme:

The novel compounds of formula I may be applied to a great number of crop plants such as cereals, potatoes, cotton or peanut, before or after the emergence of the plants, in order to combat weeds. For example, in cereals they effectively control deadnettle (Lamium), field speedwell (Veronica), goose grass (Galium), corn pansy (Viola), knotgrass (Polygonum) and ox-eye daisy (Chrysanthemum) in post-emergence application. In potatoes, cotton and peanut they are usually applied in the pre-emergent phase. The compounds may furthermore be used to combat broad-leaf weeds in lawns.

The compounds are well tolerated by crop plants. They have an activity superior to that of known commercial products having a similar application range, for

example bromofenoxim (3,5-dibromo-4-hydroxybenzaldoxime-O-Z, 4'-dinitrophenol ether) or dinoseb (2,4-dinitro-6-sec-butylphenol); as compared to products of the group of the yellow spraying agents (for example 3,5-dinitro-o-cresol or dinoseb) they have the advantage of not dyeing the plants.

The herbicides of the invention may be present in commercial formulations of plant protecting products in varying concentrations. Depending on the specific mode of formulation they may contain from 10 to of active substance. When mixed with other active substances and/or fertilizers, the content of active substance may be decreased and amount for example to l or less.

The products are applied in dilution rates usual for herbicides, which rates depend on the weeds to combat, the crop plants to be spared, the climatic conditions, the season, the nature of the soil and other factors. In practice, dilutions of from about 0.001 to 1.0 are usual in the open field. As comparative value, the part by weight applied per surface unit of soil (kg/ha or lbs/acre) is often indicated.

The compounds may be applied in the form of wettable powders, emulsifiable concentrates, dusting powders or granules, alone, or optionally, in combination with other herbicides, soil insecticides or also with fertilizers.

Wettable powders are preparations which are homogeneously dispersible in water, and which, in addition to the active substance and an inert substance, contain also wetting agents, for example polyoxethylated alkylphenols, polyoxethylated oleyl or stearyl amines, or alkyl or alkylphenyl-sulfonates, and dispersing agents,

for example the sodium salts of lignin-sulfonic acid, 2,-,

2-dinaphthyl-methane-6,6-disulfonic dibutylnaphthalene-sulfonic acid, or taurine.

Emulsifiable concentrates may be obtained by dissolving the active ingredient in an organic solvent, for example butanol, cyclo-hexanone, dimethyl formamide, xylene, or higher boiling aromatics. In order to obtain a good emulsion in water, further wetting agents from the above series may be added.

Dusting powders are obtained by grinding the active substance with finely divided solid substances, for example talcum or natural aluminates, pyrophyllite or diatomaceous earth.

Granules may be obtained either by atomizing the active substance through a nozzle onto an absorptive granulated inert material, or by applying a concentrate of the active ingredient by means of an adhesive, for example polyvinyl alcohol, the sodium salt of polyacrylic acid or mineral oils, onto the surface of granulated inert materials. The active substances may also be granulated by the methods used in the preparation of fertilizer granulated material, if desired in admixture with one or more fertilizers.

The following Examples illustrate the invention.

EXAMPLE 1 a. 4-difluoro-methylthio-1-chlorobenzene Cl-Q-SCF a 4000 ml of 1,2-dimethoxy-ethane were added to a sodium-4chloro-thiophenolate solution, prepared by dissolving 2075 g (51.8 moles) of caustic soda in 2300 g of water and adding 1500 g (10.4 moles) of 4- chlorothiophenol. The resulting mixture was heated to 68 70C, and subsequently 1400 g (16.7 moles) of gaseous difluoro-chloromethane were introduced into the solution with intense agitation. After the indicated acid, oleylmethylamount of CHClF was added the reaction mixture was I vacuo. After elimination of the methylene chloride and the residual 1,2-dimethoxy-ethane, the residue was vacuum-distilled.

The yield was 1870 g (92 relative to the 4- chlorothiophenol used) of 4-difluoro-methylthio-lchlorobenzene.

Boiling point: 94 96C (16 17 mm) (lit.:) 62 64C (0.3 mm) chlorobenzene Clii -SCF CFCll-l 97 g (1.7 moles) of pulverized caustic potash were added to a solution of 498 g (3.4 moles) of 4- chlorothiophenol in 800 ml of acetonitrile. Subsequently, at a maximum temperature of 60C, 101 g (3.4 moles) of trifluoro-chloroethylene were introduced with agitation into the mixture formed. After the gas had been introduced, the reaction mixture was maintained at 60C for another hour.

The potassium hydroxide precipitated from the cooled reaction mixture was separated by suctionfiltration, and water was added to the filtrate until the thioether formed precipitated in the form of an oil, which was separated from the aqueous phase by extraction with methylene chloridev The methylene chloride phase was washed, dried and concentrated. The residue consisted of 683 g of an oil, from which the pure product was obtained by vacuum distillation.

The net yield was 625 g (69.8 relative to the 4- chlorothiophenol used) of 4-(1,1,2-trifluoro-2'- chloroethylthio)-chlorobenzene.

Boiling point: 94 -96C (1.5 1.6 mm) c. 4-difluoro-methylsulfonyll -chlorobenzene 1750 g of 33 aqueous hydrogen peroxide solution were added dropwise with agitation to a solution of 1000 g (5.14 moles) of 4-difluoro-methylthio-1- chlorobenzene in 3500 ml of glacial acetic acid preheated to an internal temperature of 100C in such a manner that the reaction temperature was maintained without additional heating. Agitation was continued for another hour at 100C. Subsequently, the reaction mixture was cooled to room temperature and stirred into a mixture of ice and water. The crude precipitate was collected on a suction filter, washed to neutral with large amounts of water and dried by suction. It was then purified by dissolving in boiling benzene, separation of the water still adhering, cooling of the benzene solution and suction-filtration of the precipitated crystals.

1078 g (92.6 relative to the thio ether amount used) of 4-difluoro-methylsulfonyl-l-chlorobenzene were obtained. Melting point: 67 68C (lit.: 67C).

d. V 4-difluoro-methylsulfony1-2-nitrol chlorobenzene Cl so or, H

214 ml of fuming nitric acid were added dropwise with agitation to a solution of 683 g (3.0 moles) of 4- difluoromethylsulfonyl-l-chlorobenzene in 1850 ml of concentrated sulfuric acid at a temperature of from 70 to 80C. The mixture was maintained at this temperature for 1 hour. After cooling to room temperature, the mixture was introduced into ice/water, the crude precipitate was decanted several times with water, washed to neutral on a suction filter and finally recrystallized from methanol. 777 g (94.5 of 4-difluoromethylsulfonyl-2-nitro-1-chlorobenzene were obtained.

Melting point 72 74C e. 4-difluoro-methylsulfonyl-2-nitro-l-aminobenzene I s0 N02 1 cr a A solution of 100 g (3.7 moles) of 4-difluoromethylsulfonyl-Z-nitro-l-chlorobenzene in 4000 ml of 99 ethanol in an autoclave was saturated with gaseous ammonia at a pressure of 7 atm/g, and heated for 10 hours at about 60 70C. After cooling to room temperature and release of the pressure, the contents of the pressure vessel were introduced into the 10-fold amount of water, the crude precipitate was collected on a suction-filter and crystallized from ethanol. 846 g (91 of 4-difluoro-methylsulfonyl-2-nitro- 1 aminobenzene were obtained which, according to the thin-layer chromatogram, were free from starting product.

Melting point 168 169C f. 4-difluoro-methylsulfonyl-1,Z-diaminobenzene 20 g of a nickel catalyst on kieselguhr were added to a solution of 400 g (1.6 moles) of 4-difluoromethylsulfonyl-Z-nitro-l-aminobenzene in 4000 ml of 99 ethanol in an autoclave, and the whole was hydrogenated for 10 hours at 60 70C under a hydrogen pressure of about 100 atm/g. After cooling and release of the pressure, the ethanolic solution of the crude product was filtered off and concentrated to dryness with reduced pressure.

348 g (99 of 4-difluoro-methylsulfonyl-1,2- diaminobenzene were obtained, a product sufficiently pure for the subsequent reaction.

Melting point (from toluene) 128 -129C.

g. 2-trifluoromethyl-S-difluoro-methylsulfonyl- CF r CF H 199 g (0.9 mole) of 1,2-diamino-4-difluoromethylsulfonylbenzene were refluxed for about 3 hours (bath temperature 110C) with 308 g (2.7 moles) of trifluoroacetic acid. Subsequently, the trifluoroacetic acid in excess was distilled off together with the water formed, finally under reduced pressure. The remaining solid residue was recrystallized from acetonitrile.

Net yield 233 g (81.5 melting point l 182C.

TABLE Physical data of the preliminary products obtained according to Example la to If Cl Q R H CF H CFClH HS boiling point b.p.

9496C 9496C 5 (16-17 mm) (1.5- l 6 mm) CF2R 6768C 4Z43C 5354C 2 (benzene) (crude) (gasoline) CF R Cl 4U m.p. 7274C 5657C 83C 2 N0 (methanol) (ethanol) (ethanol) CF R m.p. l68l69C ll7l 18C l26-127C $0 N02 (ethanol) (ethanol) (ethanol) l CF R NH m m.p. 128-129C 56 57C 87-88C SO NH (cyclohexane) (crude) (toluene) CF R EXAMPLE 2 a l CF 30 N/ i 2 H CF cF H 46 g (0.15 mole) of 1,2-diamino-4-tetrafluoroethylsulfonylbenzene were refluxed for about 3 hours (bath temperature about 100 -110C) with 23 g (0.2 mole) of trifluoro-acetic acid. Subsequently, the excess trifluoro-acetic acid was distilled off together with the water formed during the cyclization (at last with reduced pressure). The remaining residue was recrystallized from chloroform.

Net yield: 35 g, m.p. 109 111C EXAMPLE 3 S Cr b 60 g (0.2 mole) of 1,2-diamino-4-( l ,1 ',2-trifluoro- 2 2'-chloro)-ethylsulfonylbenzene were refluxed for about 1 hour (bath temperature 100 1 C) with 69 g (0.3 mole) of trifluoro-acetic acid. Subsequently, the non-consumed trifluoro-acetic acid was distilled off together with the water formed during the cyclization, at last under reduced pressure. The crude product remaining as residue was recrystallized from chloroform.

Net yield: 46.5 g, m.p. 112 114C EXAMPLE 4 -CF or, N/ so H EXAMPLE 5 -cF ccl H so, H

33.3 g (0.15 mole) of 1,2-diamino-4-difluoromethylsulfonylbenzene were dissolved in 100 ml of glacial acetic acid and, after addition of 29 g (0.15 mole) of 1,1-difluoro-2,Z-dichloroiminopropionic acid methyl ester, heated for about 3.5 hours at 60 70C (internal temperature). After cooling, the reaction mixture was digested several times with icewater. The crude product remaining as water-insoluble residue was absorbed in chloroform, the chloroform solution was dried and concentrated. The residue crystallizing on trituration was recrystallized from chloroform.

Net yield: 32 g, m.p. 142 144C EXAMPLE 6 54 g (0.2 mole) of l,2-diamino-4-(1,1',2,2- tetrafluoro)-ethylsulfonylbenzene were dissolved in 200 ml of glacial acetic acid, and, after addition of 42 g (0.22 mole) of l ,1-difluoro-2,2-dichloroiminopropionic acid methyl ester, heated to 60 70C (internal temperature). Subsequently, icewater was added to the cooled reaction mixture, the water decanted from the oily crude product precipitated and the product was several times digested with water. The viscous oil remaining was dissolved in methylene chloride, the solution was washed with water, dried over calcium chloride and concentrated. The oily residue solidified after a several hour standing at room temperature to form a mass of crystals, which was purified by intense dispersing by means of an Ultra-Turrax device in carbon tetrachloride in which the product is only scarcely soluble, and by subsequent suction-filtration of the fine crystals.

Net yield: 56 g, m.p. 89 95C.

EXAMPLE 7 2 (BF, CFClH 43.5 g (0.15 mole) of l,2-diamino'4-(l,1,2'- trifluoro-2-chloro)-ethylsulfonylbenzene were dissolved in 150 ml of glacial acetic acid and, after addition of 29 g (0.15 mole) of 1,1-difluoro-2,2-dichloroimino-propionic acid methyl ester, heated for 3 hours at C (internal temperature). lcewater was added to the cooled reaction mixture; the precipitated crude product, after decanting, was digested several 50 times with water. The residue was absorbed in chloroform, the chloroform solution was washed with water, dried and concentrated. The crude product which resulted was recrystallized from carbon tetrachloride with addition of active charcoal.

Net yield: 57 g, m.p. 103 106C.

EXAMPLE 8 A water-dispersible wettable powder was obtained by preliminary grinding 12 parts by weight (6)difluoromethylsulfonyl-benzimidazole with 3 parts by weight of finely disperse silicic acid, then adding I 43 parts by weight of a preliminary mixture containing 10 g of cellulose pitch 49 g of Sillitin Z (quartz Al-Silicate) 8 g of finely disperse silicic acid 7 g of polypropylene oxide (molecular weight 750)/silicic acid 1:1 1 g of sodium salt of oleylmethyltauride, mixing the whole and grinding it in a disk attrition mill.

EXAMPLES OF APPLICATION EXAMPLE 1 Seeds of weeds and crop plants were sowed in pots filled with loam earth and covered with flat covers. The

day of sowing, the surface of the soil was sprayed with different doses of a wettable powder formulation of the active substance according to Example 1 g suspended in water. As somparative agents, 2 known benzimidazole derivatives were used, namely comparative agent A according "to German Offenlegungsschrif't; Ne. 1.770.658

German N0.

according Offenlegungsschrift 1 .770.658

comparative agent B according to Belgian -v I Patent No. 659.

according to Belgian Pat. No. 659.384

The results of these treatments as well as the results of all following Examples were evaluated according to the following scheme of values:

% of damage in value index weeds crop plants l 100 O 2 97,5 to 100 0 to 2,5 3 95 to 97,5 2,5 to 4 90 to 95 5 to 5 85 to 90 10 to 6 75 to 85 15 to 7 65 to 75 25 to 8 32,5 to 65 35 to 67.5 9 0 to 32,5 67,5 to 100 The index 4 indicates a degree of activity against weeds or an absence of detrimental effects in crop plants that is still acceptable (cf. Bolle, Nachrichtenblatt des Deutschen Pflanzenschutzdienstes 16, 1964, 92 94).

4 weeks after treatment the following results listed in TABLE IC0ntinued Greenhouse test, preemergence treatment; dosage in kg/ha of active substance plant species active substance comparative comparative according to agent A agcnt B Example 1g) Poa l 9 8 Sinapis l 8 8 Stellaria l 7 8 Crop plants: peanut l l l cotton 1 l 1 EXAMPLE II A wettable powder formulation of the substance of the invention according to Example 1 g suspended in water was sprayed on weeds in the postemergence phase in a greenhouse. For comparative purposes the same known substances A and B were used. 4 weeks after the treatment, the following result was obtained:

TABLE II Greenhouse test. postemergence treatment; dosages in kg/ha of active substance active plant species substance according to comparative comparative Example 1g) agent A agent B Lamium 1 3 3 7 4 7 Galium 2 5 4 8 5 9 Veronica 2 4 4 6 5 8 Viola l l l 5 2 7 Stellaria l l 3 4 5 9 Matricaria 1 1 2 7 5 8 EXAMPLE III In a greenhouse test, the compound of Example lg was compared with the known commercial product dinoseb acetate (2,4-dinitro-6-sec.-butylphenyl acetate). For this purpose, wettable powder formulations of both active substances were sprayed onto the emerged weeds in the 2 to 3-leaf stage. In the same manner barley and wheat were treated. 3 weeks after treatment the following result was obtained:

TABLE III Greenhouse test, postemergence treatment; dosages in kg/ha of active substance active substance according to plant species dinoseb acetate Example 1g) 0.62 0.31 0.15 0.62 0.31 0.15

Weed grasses:

Alopecurus 2 7 9 8 9 9 Apera 1 3 6 8 8 9 Bromus 4 8 9 8 9 9 Poa 3 5 8 8 8 9 Weeds:

Amaranthus 1 l l 5 7 8 Anthemis 1 1 1 1 3 6 Chenopodium l 1 l 1 l l Chrysanthemum l l l l 3 5 Galium 3 4 8 8 9 9 Matricaria 1 1 1 1 4 7 TABLE [ll-Continued weeks after treatment, the following result was obtained:

Greenhouse test, postemergence treatment; dosages in kg/ha of active substance TABLE VI pllm poems lulu substance Greenhouse test, preemergence treatment; dosages in kg/ha of active according to dinoseb acetate 1 I substance Example (lg) 0462 0.31 015 0,62 0.3l ()ll5 plant species active substance Sinapis l 2 5 l 5 7 according to monolinuron Stellaria l l 3 5 6 8 Example (lg) Viola l l l 7 8 9 10 2.5 0.62 2.5 0.62

Crop plants: weeds barley l l l l l 1 P 1 3 1 2 Wheat 1 l l l l l s i 1 1 1 1 Polygonum l l l l Stellaria l l l 1 l5 Chenopodium l l l l Matricaria l l l 3 EXAMPLE lV Crop plant t' t l l 6 2 In a similar greenhouse test the substance of Example PO A De lg was compared with dinoseb acetate and bromofenoxim (3,5-dibrorno-4-hydroxy-benzaldoxime-0-2,4'- EXAM LE V" dinitrophenyl-ether) with respect to its activity against Galium. 3weeks after treatment, the following result In a field test using com, the substance of Example was obtained: 1 g was compared with the commercial product atrazine TABLE [V Greenhouse test, postemergence treatment; dosages in kg/ha of active substance active substance plant species according to Example (lg) dinoseb-acetate bromofenoxim 2.5 1.25 0.62 2.5 1.25 062 2.5 1.25 0.62

Weed:

Gfllium V l l 4 Z 7 8 2 5 7 Crop plant: wheat 2 l l 4 l l l l 1 EXAMPLE V (2-chloro-4-ethylamino-6-isopropylamino-1,3,5- S l i f h Substance f E l 1 g d of triazine). For this purpose, both active substances after eral commercial products were sprayed on a freshly the p Plant had been sowed, Were p y 0n Sepasowed lawn heavily infested with Stellaria. The result is at ar as each measuring 10 m The result is listed in listed in the following Table V: the following Table VII:

TABLE V Field test, postemergence treatment; dosages in kg/ha of active substance active substance plant according to species Example (1g) ioxyn l dinoseb-acetate bromofenoxim 1.0 L0 2.0 2.0

Weed:

Stellaria 2 5 6 6 Crop plant Lawn (freshly sowed) l l 1 EXAMPLE VI TABLE VII Field test, preemergence treatment; dosages in kg/ha of active In a greenhouse test, seeds of various weeds were Substance sowed in pots. Simultaneously, potatoe tubers were planted in pots. The same day, a wettable powder susactive subsame 5 plant species according to atrazine pension of the substance of Example lg was sprayed on Example (lg) the surface of the soil. As comparative agent, the commercial product monolinuron (N-4-chlorophenyl-N- w methyl-N-methoxy-urea) was used. Echinochloa 2 6 TABLE VII-Continued TABLE VIII Field test. preemcrgencc treatment; dosages in kg/ha of active substance active substance plant species according to atrazine Example lg) Digitaria l 7 dicotylous species*) I l crop plant:

CORN 1 l )dicotylous species: mixture of Sinapis, Scnccio. Stellariav Veronica and Lamium EXAMPLE VIII Wettable powder formulations of the compounds of Examples 3, 4 and 2 and of several commercial products were suspended in water and sprayed on weeds in the preand postemergent phase. The result is listed in the following Table VIII:

Greenhouse tests prc preemergence treatment post postemergcnce treatment dosages in kg/ha of active substance pre active substance according to post active substance according to plant species Examples Examples 3 4 2 3 4 2 2.5 2.5 2.5 5.0 5.0 5.0

lmpomoea 3 l 4 5 i 5 4 Sinapis l l 1 l 3 3 Anthemis l l 3 l l 2 Amaranthus 3 l 2 4 l 3 Chcnopodium 5 l 2 5 l 3 Mercurialis 6 3 3 4 4 2 Stellaria l l l EXAMPLES IX TO XI TABLE IX Field test, post-emergence treatment Product application amount in kg/ha of active sub- Winter Lamium Matricaria Veronica Viola Stellaria stance rye purpureum chamomilla hederaefolia tricolor media untreated l 9 9 9 9 9 dinoseb 2.0 l 7 7 8 9 5 acetate LO 1 8 8 9 9 6 bromo- 2.0 l l l l 3 fenoxim [.0 l l 2 3 5 active substance acc. to 2.0 1 l I l I 1 Example 1.0 l l l l l l (lg) 0.5 l l l 2 l 2 TABLE X Field test, post emergence treatment Product application amount in kg/ha of active sub- Winter Lamium Matricaria Veronica Viola Stellaria stance barley purpureum chamomilla hederaefolia tricolor media untreated l 9 9 9 9 9 dinoseb 2.0 l 2 7 8 9 5 acetate 1.0 l 3 8 9 9 6 0.5 l 6 9 9 9 8 bromo- 2.0 l 2 4 5 9 6 fenoxim 1.0 l 3 5 8 9 7 0.5 l 3 6 9 9 8 active substance acc. to 2.0 l l 4 3 l 3 Example 1.0 l l 5 4 l 3 lg) 0.5 l l 5 4 '2 4 TABLE x1 Field test, post-emergence treatment Product application amount in kg/ha of active subspring Galium Mercurialis Polygon. Veronica stance barley wheat oats apan'ne annua convolvulus pcrsica untreated l l l 9 9 9 9 dinoseb 2.0 l l l 3 7 8 9 acetate 1.0 l l l 6 8 9 9 0.5 l l l 9 9 9 9 bromo- 2.0 1 l l l 3 l 2 fenoxim 1.0 1 l l 2 3 l 2 0.5 l l l 3 3 2 3 active substance acc. to 2.0 1 l l l l l Example 1.0 1 l 1 2 l l lg) 0.5 l l l 2 2 l 2 We claim: Where R is H, -CF H, CFClH or CCl H and R 1. A benzimidazole derivative of the formula is haloalkyl having 1 or 2 carbon atoms.

2. Z-trifluoromethyl-S-diflu0ro-methylsulfonyl- N 1 benzimidazole.

l'l SO, H 

1. A BENZIMIDAZOLE DERIVATIVE OF THE FORMULA
 2. 2-trifluoromethyl-5-difluoro-methylsulfonyl-benzimidazole. 